This invention relates to thermal blankets used in a medical setting to deliver a bath of a thermally-controlled medium to a patient.
The thermal blanket prior art is best expressed in prior U.S. Pat. No. 4,572,188 entitled "AIRFLOW COVER FOR CONTROLLING BODY TEMPERATURE", which is assigned to the assignee of this application. In this prior patent, a self-erecting, inflatable airflow cover (the "Augustine" airflow cover) is inflated by the introduction into the Augustine cover of a thermally-controlled inflating medium, such as warmed air. When inflated, the Augustine cover self-erects about a patient, thereby creating an ambient environment about the patient, the thermal characteristics of which are determined by the temperature of the inflating medium. Holes on the underside of the Augustine airflow cover exhaust the thermally-controlled, inflating medium from inside the cover to the interior of the erected structure. This airflow cover is intended for the treatment of hypothermia, as might occur postoperatively.
Evaluation of the Augustine airflow cover by skilled practitioners has resulted in general approbation: the opinion is that the cover efficiently and effectively accomplishes its purpose of giving a thermally-controlled bath. It has been realized, however, that, while the Augustine airflow cover achieves its objective, certain improvements to it are necessary in order to realize additional clinical objectives and to enjoy further advantages in its use.
The clinical usefulness of the Augustine airflow cover has been improved by numerous developments, as set forth in the aforementioned related applications. These include controlling the contour of the inflatable portion of the cover at its head end to define a generally concave non-inflatable portion that permits a care giver to more easily observe a patent's head, face, neck and chest. Further, venting of the thermally controlled inflating medium from the edges of the cover results in more efficient, more uniform heating within and under the cover. Modification has been made of the foot end of the cover to define a non-inflatable but erectable drape section which retains heat from the inflating medium to warm the patient's feet and insulate the bare skin of the feet from excessive heat from the inlet hose.
These improvements have resulted in an improved thermal blanket (the "Augustine" thermal blanket) in which a self-erecting inflatable covering has a head end, a foot end, two edges, and an undersurface. An inflating inlet adjacent the foot end admits a thermally-controlled inflating medium into the covering. An aperture array on the undersurface of the covering exhausts the thermally-controlled inflating medium from the covering into the structure created when the covering self-erects upon inflation. The improvements to this basic structural complement include an uninflatable section at the head end of the covering, exhaust port openings at the edges of the covering, an absorbent bib attached to the covering at the head end adjacent the uninflatable section, an uninflatable erectable drape section at the foot end of the covering, and structural features that make the covering simple and economical to produce.
With these improvements, the Augustine thermal blanket, when inflated and erected over a patient, delivers the thermally-controlled inflating medium into the interior of the structure covering the patient, thereby thermally bathing the patient. The first improvement permits full viewing of the head and face of the patient from almost any aspect around the thermal blanket. The exhaust port openings increase the rate of circulation of the inflating medium within the blanket, thereby increasing the temperature within the structure, and making the temperature distribution more uniform. The absorbent bib soaks up and retains liquids which might otherwise spread over the blanket in the area of a patient's head. Such liquids can include the patient's own perspiration, blood, vomit, saliva, or liquids which are administered to the patient. The non-inflatable erectable drape section at the foot end of the covering retains heat around the patient's feet and insulates the bare skin of the feet.
We have observed that there is a need in many instances for a thermal blanket that enables viewing the side areas of the upper torso or chest while the blanket is in place.